Fluid Machine

ABSTRACT

A fluid machine ( 29 A) including: a casing section ( 56 ) having a suction port ( 55 ) into which a working fluid that becomes a high pressure heated vapor flows; a housing section ( 54 ) having a discharge port ( 53 ); and a scroll section ( 51, 52 ) driven by the working fluid suctioned from the suction port ( 55 ). A bypass section ( 80 ) including: a bypass passage ( 81 ) allowing the suction port ( 55 ) to communicate with the discharge port ( 53 ); and a valve mechanism ( 83 ) opening and closing the bypass passage ( 81 ), is supported between the sections ( 56, 54 ). When the bypass passage ( 81 ) is opened, the working fluid is circulated while bypassing a driving section including the scroll section ( 51, 52 ) and a sliding section such as an anti-rotation mechanism ( 60 ). Therefore, even when the working fluid in a liquid phase flows, degradation of lubricity in the sliding section can be reduced.

TECHNICAL FIELD

The present invention relates to a fluid machine which includes a driving section that is driven by a working fluid suctioned from a suction port, and discharges the working fluid that has passed through the driving section from a discharge port.

BACKGROUND ART

Patent Document 1 discloses a fluid machine which includes a bypass passage that guides a working fluid (refrigerant) suctioned from a suction port to a discharge port while allowing the working fluid to bypass a driving section, and a valve mechanism that opens and closes the bypass passage.

REFERENCE DOCUMENT LIST Patent Document

-   Patent Document 1: Japanese Patent Application Laid-open Publication     No. 2010-236360

SUMMARY OF THE INVENTION Problems to be Solved by the Invention

However, the bypass passage of the fluid machine according to the related art causes the working fluid to circulate while bypassing the driving section and allows the working fluid that has bypassed the driving section to be discharged from a discharge port after passing a part in which a sliding section such as an anti-rotation mechanism (ball coupling) of the driving section is disposed.

Therefore, when the working fluid that is circulated while bypassing the driving section is in a liquid phase state, the working fluid (liquid refrigerant) in the liquid phase flows into the sliding section, and thus a lubricating oil of the sliding section may be caused to flow. Therefore, there is a possibility that the lubricity of the sliding section may be degraded.

An object of the invention is to provide a fluid machine capable of reducing the degradation of lubricity of a sliding section even though a working fluid is in a liquid phase when the working fluid is circulated while bypassing a driving section.

Means for Solving the Problems

In order to accomplish the object, a fluid machine according to the invention includes: a suction port into which a working fluid that becomes a heated vapor and has a high pressure flows; a driving section which is driven by expansion of the working fluid suctioned from the suction port; a discharge port from which the working fluid that has a low temperature while passing through the driving section flows; and a bypass passage which guides the working fluid suctioned from the suction port to the discharge port while allowing the working fluid to bypass a sliding section of the fluid machine and the driving section.

Effects of the Invention

In the fluid machine according to the invention, the working fluid is circulated through the bypass passage while bypassing the sliding section along with the driving section. Therefore, even when the working fluid is in a liquid phase, the degradation of lubricity, which is caused by the flow of a lubricating oil of the sliding section, can be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating the schematic configuration of a waste-heat reusing apparatus in an embodiment of the invention.

FIG. 2 is a cross-sectional view illustrating a pump-integrated expander incorporated in the waste-heat reusing apparatus.

FIG. 3 is a partial enlarged cross-sectional view illustrating a bypass section included in the pump-integrated expander.

MODE FOR CARRYING OUT THE INVENTION

Hereinbelow, an embodiment of the invention will be described in detail with reference to the accompanying drawings.

FIG. 1 illustrates a waste-heat reusing apparatus 1A for a vehicle, in which an expander as a fluid machine is incorporated.

The waste-heat reusing apparatus 1A is an apparatus that is mounted in the vehicle along with an engine 10 and recovers waste heat of the engine 10 for use.

The waste-heat reusing apparatus 1A includes a Rankine cycle device 2A, a transmission mechanism 3 which transmits the output of the Rankine cycle device 2A to the engine 10, and a control unit 4.

The engine 10 is an internal combustion engine provided with a water-cooling type cooling device, and the cooling device includes a coolant circulation passage 11 through which a coolant is circulated.

An evaporator 22 of the Rankine cycle device 2A is disposed in the coolant circulation passage 11 so that the coolant that absorbs heat from the engine 10 is returned to the engine 10 after passing through the evaporator 22.

The Rankine cycle device 2A recovers the waste heat of the engine 10 from the coolant of the engine 10 and converts the recovered heat into driving force so as to be output.

The Rankine cycle device 2A includes a circulation passage 21 through which a working fluid is circulated, and in the circulation passage 21, the evaporator 22, the expander 23, a condenser 24, and a pump 25A are arranged in this order along the flow direction of the working fluid.

As the working fluid (refrigerant), for example, a substance which includes a fluorocarbon skeleton as a base is used. In addition, a lubricating oil circulates along with the working fluid and has functions of lubricating, sealing, cooling, and the like in sliding sections of the expander 23 and the pump 25A.

The evaporator 22 allows heat transfer between the high-temperature coolant that has absorbed heat from the engine 10 and the working fluid of the Rankine cycle device 2A so that the working fluid is heated and evaporated (vaporized).

The expander 23 (fluid machine) is a device which generates driving force by expanding the working fluid that has a high temperature and a high pressure through the vaporization in the evaporator 22, and uses, as an example, a scroll type expander.

The condenser 24 allows heat exchange between the low pressure working fluid that has passed through the expander 23 and the outside air to cool the working fluid so as to be condensed (liquefied).

The pump 25A is a mechanical pump and forcibly feeds the working fluid liquefied in the condenser 24 to the evaporator 22.

In this manner, the working fluid circulates through the circulation passage 21 while repeating vaporization, expansion, and condensation.

Here, the expander 23 and the pump 25A are connected by a rotating shaft 28 to be integrated, thereby providing a pump-integrated expander 29A (fluid machine). That is, the rotating shaft 28 of the pump-integrated expander 29A functions as the output shaft of the expander 23 and functions as the driving shaft of the pump 25A.

The Rankine cycle device 2A is first started up by driving the pump 25A by the output of the engine 10, and thereafter, when the expander 23 generates sufficient driving force, the driving force of the expander 23 drives the pump 25A.

The transmission mechanism 3 transmits the torque (axial torque) of the pump-integrated expander 29A, which is the output of the Rankine cycle device 2A, to the engine 10 and transmits the output torque of the engine 10 to the pump-integrated expander 29A (pump unit) during start-up of the Rankine cycle device 2A.

The transmission mechanism 3 includes a pulley 31 attached to the rotating shaft 28 of the pump-integrated expander 29A, a crank pulley 32 attached to a crankshaft 10 a of the engine 10, a belt 33 wound around the pulley 31 and the crank pulley 32, and an electromagnetic clutch 34 provided between the rotating shaft 28 of the pump-integrated expander 29A and the pulley 31.

By turning on (engaging) and turning off (disengaging) the electromagnetic clutch 34, power transmission and power interruption between the engine 10 (crankshaft 10 a) and the rotating shaft 28 of the pump-integrated expander 29A are switched.

The control unit 4 having a microcomputer has a function of controlling the electromagnetic clutch 34, and controls an operation and a stop of the Rankine cycle device 2A through the on and off control of the electromagnetic clutch 34.

That is, when the control unit 4 determines the establishment of the operating conditions of the Rankine cycle device 2A, the electromagnetic clutch 34 is engaged (turned on) and the pump 25A is operated by the engine 10 to start the circulation of the working fluid (refrigerant), thereby starting up the Rankine cycle device 2A.

When the expander 23 is activated and starts to generate a driving force, a part of the driving force generated by the expander 23 is used to drive the pump 25A, and the remaining driving force is transmitted to the engine 10 via the transmission mechanism 3 to assist the output (driving force) of the engine 10.

In a case in which the operating conditions of the Rankine cycle device 2A are not established, the control unit 4 disengages (turns off) the electromagnetic clutch 34 to stop the circulation of the working fluid, thereby stopping the Rankine cycle device 2A.

The evaporator 22 may also act as a device that allows heat exchange between the working fluid of the Rankine cycle device 2A and exhaust air of the engine 10 or may also act as a device that allows heat exchange with the coolant of the engine 10 and allows heat exchange with exhaust air of the engine 10.

The expander 23 integrally includes a bypass passage 81 for circulating the working fluid to bypass a scroll portion provided as a driving portion and a valve mechanism 83 for opening and closing the bypass passage 81.

In addition, for example, the control unit 4 controls the valve mechanism 83 to be opened so as to open the bypass passage 81 immediately after the start-up of the Rankine cycle device 2A at which the electromagnetic clutch 34 is engaged so that the working fluid is circulated while bypassing the scrolls of the expander 23.

Thereafter, for example, when the refrigerant temperature at the inlet of the expander 23 exceeds a threshold, in other words, when the expander 23 can generate driving force, the control unit 4 controls the valve mechanism 83 to be closed to close the bypass passage 81, to thereby perform a changeover to a state in which the working fluid is circulated while passing through the scrolls.

As described above, when the working fluid is circulated while bypassing the scrolls of the expander 23 immediately after the start-up of the Rankine cycle device 2A, the pressure in the evaporator 22 decreases and the evaporation temperature of the working fluid also decreases. Therefore, the start-up performance of the Rankine cycle device 2A can be improved. In addition, at the time of stopping the Rankine cycle device 2A, when the electromagnetic clutch 34 is disengaged (turned off), the bypass passage 81 is opened so as to prevent high-speed rotations due to the residual pressure.

Next, the structure of the pump-integrated expander 29A will be described in detail with reference to FIG. 2.

As described above, the pump-integrated expander 29A is a fluid machine in which the pump 25A that circulates the working fluid of the Rankine cycle device 2A and the expander 23 that generates rotational driving force through the expansion of the working fluid heated and vaporized in the evaporator 22 are driven by the common rotating shaft 28, and includes the pulley 31 and the electromagnetic clutch 34 included in the transmission mechanism 3.

The expander 23 of the pump-integrated expander 29A includes a fixed scroll 51 which is disposed in one end portion of the pump-integrated expander 29A in the axial direction, an orbiting scroll (movable scroll) 52 assembled to be eccentrically engaged with the fixed scroll 51, a housing section 54 provided with a discharge port 53, and a casing section 56 provided with a suction port 55.

The fixed scroll 51 includes a disc-like body portion 51 a, a scroll portion (spiral body) 51 b uprightly provided on one end surface of the body portion 51 a in a rib shape, and an introduction port 51 c for the working fluid, which is formed to penetrate through the center of the body portion 51 a.

The housing section 54 is formed in a cylindrical shape with both ends opened, and includes a first hollow portion 54 a into which the casing section 56 is fitted and which accommodates the fixed scroll 51 and the orbiting scroll 52, a second hollow portion 54 b which supports a large-diameter portion 64 included in a driven crank mechanism between the orbiting scroll 52 and the rotating shaft 28, and a third hollow portion 54 c which supports the rotating shaft 28.

In addition, on the pump 25A side of the first hollow portion 54 a, the discharge port 53 which allows the internal space (discharge side space of the scrolls) of the first hollow portion 54 a to communicate with the external space is formed along the radial direction of the rotating shaft 28.

The casing section 56 includes a cylindrical portion 56 a which is provided integrally with the fixed scroll 51 on the inside and of which the outside is fitted into the first hollow portion 54 a, and a working fluid introduction chamber 56 b which communicates with the introduction port 51 c of the fixed scroll 51. The suction port 55 which allows the working fluid introduction chamber 56 b to communicate with the external space of the casing section 56 is formed along the radial direction of the rotating shaft 28.

Here, the discharge port 53 and the suction port 55 are substantially parallel to each other, extend in a direction at the same angle from the axis of the rotating shaft 28, and are arranged in the axial direction of the rotating shaft 28.

To the suction port 55, one end of a pipe, the other end of which is connected to the outlet of the evaporator 22, is connected so that the working fluid heated in the evaporator 22 is introduced into the expander 23 via the suction port 55.

The working fluid introduced into the suction port 55 flows into the working fluid introduction chamber 56 b and thereafter is introduced to the center portion of the fixed scroll 51 via the introduction port 51 c.

The working fluid introduced to the center portion of the fixed scroll 51 presses the wall surface of the orbiting scroll 52 to form an expansion chamber, and as the working fluid is continuously supplied, the expansion chamber moves to the outer circumferential side, which causes an orbiting motion of the orbiting scroll 52.

To the discharge port 53, one end of a pipe, the other end of which is connected to the inlet of the condenser 24, is connected so that the working fluid which passes through the expander 23 is sent to the condenser 24 to be condensed (liquefied).

The orbiting scroll 52 includes a disc-like body portion 52 a and a scroll portion (spiral body) 52 b uprightly provided on one end surface of the body portion 52 a in a rib shape.

Here, an anti-rotation mechanism 60 is provided between the surface of the body portion 52 a on the opposite side to the end surface thereof in which the scroll portion 52 b is formed, and a stepped portion 54 d which reaches the second hollow portion 54 b from the first hollow portion 54 a of the housing section 54 so that the orbiting scroll 52 makes orbiting motion as the working fluid expands while being prevented from rotating by the anti-rotation mechanism 60.

As the anti-rotation mechanism 60, there are an Oldham coupling, a pin and ring coupling, a ball coupling, and the like. Here, the ball coupling is used, and particularly, a ball coupling called an EM coupling (refer to “EM coupling for Scroll Compressors” in NTN TECHNICAL REVIEW No. 68 (2000)) is used. The EM coupling is constituted by two plates made by integrally press-forming the race and the ring, steel balls, and the like.

A cylindrical portion 52 c protrudes from the end surface of the body portion 52 a of the orbiting scroll 52 on the anti-rotation mechanism 60 side, and a drive bearing 61 is provided on the inside of the cylindrical portion 52 c. An eccentric bush 62 is fitted into the drive bearing 61, and a crankpin hole 62 a is formed in the eccentric bush 62.

The large-diameter portion 64 is rotatably supported by the second hollow portion 54 b of the housing section 54 via a bearing 63, and a crankpin 64 a is uprightly provided on the large-diameter portion 64 so that the crankpin 64 a is parallel to the rotating shaft 28 and has an axial center shifted from the rotating shaft 28. The crankpin 64 a is inserted into the crankpin hole 62 a of the eccentric bush 62.

The rotating shaft 28 is connected to the large-diameter portion 64 so that the orbiting motion of the orbiting scroll 52 around the rotating shaft 28 is transmitted as the rotational driving force of the rotating shaft 28 by the driven crank mechanism constituted by the eccentric bush 62, the crankpin 64 a, and the large-diameter portion 64.

In addition, a counterweight (balancing weight) 74 for reducing occurrence of vibrations of the expander 23 is attached to the eccentric bush 62.

Furthermore, in order to restrict the orbiting radius of the orbiting scroll 52, a restriction hole 64 b is provided in the large-diameter portion 64, and a restriction protrusion 62 b fitted into the restriction hole 64 b is provided in the eccentric bush 62. Therefore, the oscillation of the eccentric bush 62 around the crankpin 64 a is restricted by the engagement between the restriction hole 64 b and the restriction protrusion 62 b.

The rotating shaft 28 is supported by a bearing 65 provided in the third hollow portion 54 c of the housing section 54 and is supported by a bearing 67 provided in the end portion of a pump housing 66 connected to the housing section 54 so as to rotate.

The pump 25A is provided in the pump housing 66. The pump 25A is, as an example, a gear pump, and the gear pump is constituted by a driving gear (rotating body) that is axially supported by the rotating shaft 28, a driven shaft that is rotatably supported in parallel to the rotating shaft 28, and a driven gear that is axially supported by the driven shaft and is engaged with the driving gear.

In the pump housing 66, a pump suction port 66 a which communicates with the suction port of the pump 25A, and a pump discharge port 66 b which communicates with the discharge port of the pump 25A are formed.

To the pump suction port 66 a, one end of a pipe, the other end of which is connected to the outlet of the condenser 24, is connected so that the working fluid condensed (liquefied) in the condenser 24 is suctioned into the pump 25A. In addition, to the pump discharge port 66 b, one end of a pipe, the other end of which is connected to the inlet of the evaporator 22, is connected so that the working fluid condensed (liquefied) in the condenser 24 is forcibly fed to the evaporator 22 to be evaporated (vaporized).

As the pump 25A, a well-known pump may be appropriately employed, and other than the gear pump, a vane pump or the like may be used.

On the end portion of the rotating shaft 28 that passes through the pump housing 66 and extends to the outside, the pulley 31 and the electromagnetic clutch 34 included in the transmission mechanism 3 are disposed.

A cylindrical portion 66 c in which the rotating shaft 28 is positioned is formed integrally with the end surface of the pump housing 66 on the opposite side to the expander 23 side. The bearing 67 which supports the rotating shaft 28 is disposed on the front end side of the inside of the cylindrical portion 66 c, and a shaft seal 68 is disposed on the bottom portion side (the expander 23 side) of the cylindrical portion 66 c.

In addition, a clutch plate 71 is attached to the front end of the rotating shaft 28 that protrudes from the cylindrical portion 66 c, and the pulley 31 is rotatably attached to the outer circumference of the cylindrical portion 66 c via a bearing 72.

Furthermore, a clutch coil 73 is accommodated in an annular groove 31 a that is formed in the end surface of the pulley 31 on the expander 23 side and is centered on the rotating shaft 28, and the electromagnetic clutch 34 is constituted by the clutch plate 71 and the clutch coil 73.

When the clutch coil 73 is electrically connected, magnetic attraction occurs and the clutch plate 71 is brought into contact with the pulley 31 such that the pulley 31 and the clutch plate 71 (rotating shaft 28) are interlocked with each other. As a result, power is transmitted between the rotating shaft 28 of the pump-integrated expander 29A and the engine 10 (crankshaft 10 a).

The expander 23 of the pump-integrated expander 29A further includes a bypass section 80 for guiding the working fluid suctioned from the suction port 55 to the discharge port 53 while allowing the working fluid to bypass the driving section (scroll section) including the fixed scroll 51 and the orbiting scroll 52, and the sliding sections such as the anti-rotation mechanism 60.

The bypass section 80 includes a holder 82 in which the bypass passage 81 is formed, and the valve mechanism 83 which is supported by the holder 82 and opens and closes the bypass passage 81, and is supported between the casing section 56 provided with the suction port 55 and the housing section 54 provided with the discharge port 53.

In addition, the valve mechanism 83 is a solenoid valve having a coil 83 d. A shim 96 is fixed between the holder 82 and the casing section 56 and between the housing section 54 and the casing section 56.

Hereinbelow, details of the bypass section 80 will be described with reference to FIG. 3.

The holder 82 includes a front end portion 82 a in which the bypass passage 81 is formed and a base end portion 82 b which holds the coil 83 d of the valve mechanism 83 and the like, and the front end portion 82 a is supported between the casing section 56 and the housing section 54 in the axial direction of the rotating shaft 28.

An accommodation space 91 for supporting the front end portion 82 a of the holder 82 is provided between a part in which the suction port 55 of the casing section 56 is formed and a part in which the discharge port 53 of the housing section 54 is formed. The accommodation space 91 is a space which is surrounded by the casing section 56 and the housing section 54 with a bottom and is open to the radially outer side of the rotating shaft 28.

A suction side communication passage 92 which communicates with the suction port 55 is open to the surface of the accommodation space 91 that is on the casing section 56 side and configured to support the front end portion 82 a of the holder 82 in the axial direction. In addition, a discharge side communication passage 93 which communicates with the discharge port 53 is open to the surface of the accommodation space 91 that is on the housing section 54 side and configured to support the front end portion 82 a in the axial direction.

In addition, the bypass passage 81 which extends in the axial direction of the rotating shaft 28 is formed in the front end portion 82 a of the holder 82, and in a state in which the front end portion 82 a is supported between the casing section 56 and the housing section 54 in the axial direction of the rotating shaft 28, one end of the bypass passage 81 is connected to the suction side communication passage 92 and the other end of the bypass passage 81 is connected to the discharge side communication passage 93, thereby forming a bypass passage of the working fluid.

As described above, the bypass section 80 (holder 82) is disposed between the suction port 55 and the discharge port 53, and the suction port 55 and the discharge port 53 directly communicate with each other through the bypass passage 81 formed in the holder 82. In other words, the bypass passage 81 formed in the holder 82 is a communication passage that extends in the axial direction of the rotating shaft 28 and allows the suction port 55 and the discharge port 53 to directly communicate with each other.

A part of the holder 82 in which the end portion of the bypass passage 81 on the casing section 56 side is open forms a cylindrical protrusion 82 c which protrudes in a cylindrical shape along the direction parallel to the axis of the rotating shaft 28, and the bypass passage 81 extends in the axial center of the cylindrical protrusion 82 c.

On the other hand, the suction side communication passage 92 has a fitting hole (enlarged diameter portion) 92 a having a diameter into which the cylindrical protrusion 82 c is fitted, on the holder 82 side (the housing section 54 side). That is, the suction side communication passage 92 is formed to have substantially the same diameter as the bypass passage 81 from the suction port 55 side and in the middle of the passage, the diameter thereof is enlarged to a diameter into which the outer circumference of the cylindrical protrusion 82 c is fitted.

In addition, an annular groove 82 f is formed in the outer circumference of the cylindrical protrusion 82 c and a seal member (O-ring) 94 formed of an elastic material such as rubber in an annular shape is fitted into the annular groove 82 f. When the cylindrical protrusion 82 c is fitted into the fitting hole 92 a, the gap between the outer circumference of the cylindrical protrusion 82 c and the inner circumference of the fitting hole 92 a of the suction side communication passage 92 is sealed by the seal member 94.

That is, by fitting the cylindrical protrusion 82 c into the fitting hole 92 a of the suction side communication passage 92, the bypass passage 81 is allowed to communicate with the suction port 55, and the position of the holder 82 in the radial direction of the rotating shaft 28 is determined with respect to the suction side communication passage 92 so that the gap between the cylindrical protrusion 82 c of the holder 82 and the fitting hole 92 a of the casing section 56, in other words, the suction port 55 side of the bypass passage 81, is sealed by the cylindrical seal.

Abutment between the holder 82 and the casing section 56 in the axial direction of the rotating shaft 28 is performed between a flat surface portion 82 e of the root portion of the cylindrical protrusion 82 c and a flat surface portion 56 c of the casing section 56 in which the suction side communication passage 92 is open. In addition, between the holder 82 and the casing section 56 and between the housing section 54 and the casing section 56, the shim 96 which is a fitting strip made of, for example, metal is fixed. By the shim, the gap between the fixed scroll 51 and the orbiting scroll 52 in the axial direction of the rotating shaft 28 is adjusted.

A base portion 82 g which forms an abutment surface parallel to the transverse cross-section of the rotating shaft 28 protrudes from a part of the holder 82 in which the end portion of the bypass passage 81 on the housing section 54 side is open, and a recessed portion 54 e into which the base portion 82 g is loosely inserted and which has a bottom surface (flat surface portion), which is parallel to the end surface (flat surface portion) of the base portion 82 g and to which the discharge side communication passage 93 is open, is formed in the housing section 54.

In addition, in a case in which the holder 82 is supported between the housing section 54 and the casing section 56, when the base portion 82 g is loosely inserted into the recessed portion 54 e, the bypass passage 81 on the holder 82 side and the discharge side communication passage 93 on the housing section 54 side communicate with each other, and the bypass passage 81 is connected to the discharge port 53 via the discharge side communication passage 93.

That is, the bypass passage 81 is formed from the front end of the cylindrical protrusion 82 c to the base portion 82 g (flat surface portion), and by supporting the holder 82 between the housing section 54 and the casing section 56, the suction port 55 and the discharge port 53 are allowed to communicate with each other by the bypass passage 81.

An annular groove 54 f is formed in the bottom surface of the recessed portion 54 e so as to surround the opening of the discharge side communication passage 93, and a seal member 95 formed of an elastic material such as rubber is fitted into the groove 54 f so that the abutment surface between the holder 82 and the housing section 54 is surrounded and sealed by the seal member 95. That is, the periphery of the connection portion between the bypass passage 81 on the holder 82 side and the discharge side communication passage 93 on the housing section 54 side is sealed by a flat seal. In other words, the bypass passage 81 and the discharge port 53 are sealed by the flat seal.

The seal member 95 generates a force to bias the holder 82 toward the casing section 56 side by being compressed by the holder 82, and accordingly, the holder 82 abuts on the casing section 56 side and the position of the holder 82 in the axial direction of the rotating shaft 28 is determined with respect to the casing section 56.

In addition, the holder 82 of the bypass section 80 integrally includes the valve mechanism (pilot type solenoid valve) 83 which is a solenoid valve that opens and closes the bypass passage 81.

The bypass passage 81 includes a passage 81 a that extends from the casing section 56 side in parallel to the axial direction of the rotating shaft 28 and a passage 81 b that extends from the housing section 54 side in parallel to the axial direction of the rotating shaft 28, the passage 81 a is formed at a position farther from the rotating shaft 28 than the passage 81 b, and the passages 81 a and 81 b communicate with each other through a passage 81 c that extends in the radial direction of the rotating shaft 28.

In the passage 81 c, a valve body 83 a is moved from the outside to the inside in the radial direction of the rotating shaft 28 and is seated, a seat portion 81 d for blocking the passage 81 c (bypass passage 81) in the seated state is formed, and a plunger 83 b is supported on the radially outer side in relation to the seat portion 81 d to be displaced along the radial direction.

The plunger 83 b is biased toward the seat portion 81 d (in a direction approaching the rotating shaft 28) by a coil spring (elastic body) 83 c and is displaced in a direction away from the seat portion 81 d (rotating shaft 28) by the magnetic force of the coil (solenoid) 83 d against the biasing force of the coil spring 83 c.

Here, the base end portion 82 b of the holder 82 which accommodates the coil 83 d is exposed to the outside of the casing section 56 and the housing section 54, and in the part exposed to the outside, a terminal (not illustrated) for electrical connection to the coil 83 d is provided.

The valve body 83 a is supported between the plunger 83 b and the seat portion 81 d to be displaced in the same direction (the radial direction of the rotating shaft 28) as the forward and backward direction of the plunger 83 b.

A pilot passage 83 e which penetrates through the valve body 83 a in the displacement direction thereof is formed in the valve body 83 a, and a pilot valve 83 f which blocks the opening of the pilot passage 83 e on the plunger 83 b side is formed in the front end of the plunger 83 b.

In addition, in a state in which the coil 83 d is not electrically connected, the plunger 83 b is displaced toward the seat portion 81 d by the biasing force of the coil spring 83 c and thus the valve body 83 a pressed by the plunger 83 b is seated on the seat portion 81 d. In addition, the opening of the pilot passage 83 e on the plunger 83 b side is blocked by the pilot valve 83 f, resulting in a valve closed state in which the flow of the working fluid via the bypass passage 81 is inhibited.

When the coil 83 d is electrically connected in the closed state, the plunger 83 b becomes separated from the valve body 83 a seated on the seat portion 81 d by the magnetic force of the coil 83 d, and thus the pilot valve 83 f becomes separated from the opening of the pilot passage 83 e on the plunger 83 b side such that the pilot passage 83 e is opened.

When the pilot passage 83 e is opened, the pressure in the space (main valve chamber) interposed between the valve body 83 a and the plunger 83 b decreases to the pressure on the discharge port 53 side, and a high pressure on the suction port 55 side is applied to the lower side of the outside of the valve body 83 a. Therefore, due to the pressure difference, the valve body 83 a is lifted and becomes separated from the seat portion 81 d, resulting in a valve open state in which the working fluid flows via the bypass passage 81. While the electrical connection to the coil 83 d is continued, the valve open state is maintained.

When the electrical connection to the coil 83 d is interrupted in the valve open state (electrically connected state), the plunger 83 b is displaced in a direction approaching the seat portion 81 d by the biasing force of the coil spring 83 c to block the pilot passage 83 e, and furthermore, the valve body 83 a is pressed by the plunger 83 b and is displaced in the direction approaching the seat portion 81 d. Therefore, the valve body 83 a is seated on the seat portion 81 d and returns to the valve closed state. While the non-electrical connection to the coil 83 d is continued, the valve closed state is maintained.

As described above, the valve mechanism 83 which opens and closes the bypass passage 81 is a so-called pilot type solenoid valve constituted by the valve body 83 a, the plunger 83 b, the coil spring 83 c, the coil 83 d, and the like.

The valve mechanism 83 is not limited to the pilot type solenoid valve which drives a valve body by using a pressure difference of a fluid, and may employ a direct acting solenoid valve which mechanically opens and closes a valve body by driving a movable core.

When the control unit 4 allows the coil 83 d to be electrically connected and thus allows the valve mechanism 83 to enter the valve open state so as to cause the suction port 55 and the discharge port 53 to communicate with each other through the bypass passage 81, for example, immediately after the start-up of the Rankine cycle device 2A to which the electromagnetic clutch 34 is engaged, a bypass pathway, in which the working fluid that has flowed into the expander 23 from the suction port 55 is guided to the discharge port 53 as it is via the bypass passage 81 and is discharged to the outside of the expander 23, is open. Thus, the working fluid is circulated while bypassing the scrolls 51 and 52 provided as the driving section, and the sliding sections such as the anti-rotation mechanism 60 of the orbiting scroll 52 and the drive bearing 61.

As described above, in the bypass pathway formed by the bypass passage 81, sliding sections such as the anti-rotation mechanism 60 of the orbiting scroll 52 and the drive bearing 61 are absent. Therefore, even when the working fluid in a gas-liquid mixed state or in a liquid phase state is circulated when the bypass passage 81 is open, leakage of the lubricating oil from the sliding sections can be reduced, and thus the lubricity of the sliding sections can be sufficiently kept.

Here, with regard to the arrangement of the pump-integrated expander 29A (expander 23), the direction of the suction port 55 and the discharge port 53 with respect to the vertical or horizontal direction is not limited to the above-described arrangement. However, it is preferable that the directions be set to a direction in which the leakage of the lubricating oil from the sliding sections can be reduced as much as possible when the bypass passage 81 is opened. Specifically, by installing the pump-integrated expander 29A (expander 23) so that the axial lines of the suction port 55 and the discharge port 53 are horizontal or descend in a direction from the inside to the outside of the radial direction of the rotating shaft 28, the leakage of the lubricating oil from the sliding sections, in other words, the flow of the working fluid in a liquid phase into the sliding sections can be effectively reduced. Particularly, when the axial lines of the suction port 55 and the discharge port 53 are provided to be vertically downward in the direction from the inside to the outside of the radial direction of the rotating shaft 28, the working fluid in the liquid phase can be prevented as much as possible from flowing away from the bypass pathway and flowing into the sliding sections.

In addition, since the above-described expander 23 is provided integrally with the bypass passage 81 and the valve mechanism 83 which opens and closes the bypass passage 81, compared to a case in which a bypass passage provided with a valve mechanism is connected to a pipe for circulating a working fluid, the circulation circuit of the working fluid in the Rankine cycle device 2A can be simplified.

In addition, since the holder 82 (bypass section 80) in which the bypass passage 81 is formed and the valve mechanism 83 is integrally provided is supported between the casing section 56 in which the suction port 55 is formed and the housing section 54 in which the discharge port 53 is formed, the bypass passage 81 and the valve mechanism 83 can be provided in the expander 23 (fluid machine) with a simple structure. Therefore, the processing of the expander 23 can be simplified and an increase in the axial length of the expander 23 can be reduced.

In addition, since the movement direction of the plunger 83 b and the valve body 83 a in the valve mechanism 83 is set to be in the radial direction of the rotating shaft 28, the movement spaces of the plunger 83 b and the valve body 83 a are long in the radial direction of the rotating shaft 28, and compared to a case in which the movement direction thereof is set to a direction parallel to the rotating shaft 28, the axial length of the expander 23 can be reduced.

Furthermore, since the coil (solenoid) 83 d of the valve mechanism 83 is accommodated in the base end portion 82 b of the holder 82 which is exposed to the outside of the casing section 56 and the housing section 54, heat dissipation from the coil 83 d can be efficiently performed.

In addition, since the coil (solenoid) 83 d which is a large component among the components constituting the valve mechanism 83 is disposed on the outside of the part interposed between the casing section 56 and the housing section 54, there is no need to secure the accommodation space of the coil (solenoid) 83 d to be in the part interposed between the casing section 56 and the housing section 54, and for this reason, the axial length of the expander 23 can also be reduced.

In addition, in the structure in which the holder 82 (bypass section 80) is supported between the casing section 56 and the housing section 54, one connection portion of the bypass passage 81 is sealed by a cylindrical seal and the other connection portion thereof is sealed by a flat seal. Therefore, the holder 82 (bypass section 80) can be easily positioned while blocking the leakage pathway of the working fluid.

While the contents of the invention have been described in detail with reference to the preferred embodiments, it is understood by those skilled in the art that various modifications can be made on the basis of the technical spirit and scope of the invention.

For example, the expander 23 illustrated in FIG. 2 is provided integrally with the pump 25A. However, a generator may be provided integrally with the expander 23 instead of the pump 25A or together with the pump 25A. Furthermore, the above-described bypass structure may also be applied to an expander which does not include the pump 25A or the generator.

In addition, the expander 23 may also be a rotary expander which includes a rotary piston as a driving section other than the scroll type.

In addition, the cylindrical protrusion 82 c of the holder 82 may be provided on a surface that opposes the housing section 54 so as to fit the cylindrical protrusion 82 c into the discharge side communication passage 93, and the base portion 82 g of the holder 82 may be provided on a surface that opposes the casing section 56 so as to allow the base portion 82 g to abut on the surface of the casing section 56 in which the suction side communication passage 92 is open. In other words, the connection portion of the bypass passage 81 on the housing section 54 side may be sealed by a cylindrical seal, and the connection portion of the bypass passage 81 on the casing section 56 side may be sealed by a flat seal.

In addition, the extension direction of the suction port 55 and the discharge port 53 is not limited to the radial direction of the rotating shaft 28, and for example, the suction port 55 may be configured to extend in the axial direction of the rotating shaft 28.

In addition, the bypass passage 81 may be configured not only to allow the suction port 55 and the discharge port 53 to directly communicate with each other, but also to, for example, connect the working fluid introduction chamber 56 b to the discharge port 53, or to connect the suction port 55 or the working fluid introduction chamber 56 b to a discharge side space immediately before the discharge port 53. That is, the bypass passage 81 can be modified in a range in which the bypass pathway that does not pass through the sliding sections such as the anti-rotation mechanism 60 of the orbiting scroll 52 and the drive bearing 61 is formed.

In addition, the fluid machine is not limited to the expander 23 and may be a compressor.

Furthermore, the fluid machine such as the expander 23 is not limited to being incorporated in the waste-heat reusing apparatus (Rankine cycle device).

REFERENCE SYMBOL LIST

-   1A Waste-heat reusing apparatus -   2A Rankine cycle device -   10 Engine -   21 Circulation passage -   22 Evaporator -   23 Expander -   24 Condenser -   25A Pump -   28 Rotating shaft -   29A Pump-integrated expander (fluid machine) -   31 Pulley -   34 Electromagnetic clutch -   51 Fixed scroll -   52 Orbiting scroll -   53 Discharge port -   54 Housing section -   55 Suction port -   56 Casing section -   60 Anti-rotation mechanism -   62 Eccentric bush -   80 Bypass section -   81 Bypass passage (communication passage) -   82 Holder -   82 c Cylindrical protrusion -   83 Valve mechanism -   83 a Valve body -   83 b Plunger -   83 c Coil spring -   83 d Coil -   92 Suction side communication passage -   92 a Fitting hole (enlarged diameter portion) -   93 Discharge side communication passage 

1. A fluid machine comprising: a suction port into which a working fluid that becomes a heated vapor and has a high pressure flows; a driving section which is driven by expansion of the working fluid suctioned from the suction port; a discharge port from which the working fluid that has a low pressure while passing through the driving section flows; and a bypass passage which guides the working fluid suctioned from the suction port to the discharge port while allowing the working fluid to bypass a sliding section of the fluid machine and the driving section.
 2. The fluid machine according to claim 1, wherein the bypass passage is a communication passage which allows the suction port and the discharge port to communicate with each other.
 3. The fluid machine according to claim 2, wherein the suction port and the discharge port extend in a radial direction of a rotating shaft of the driving section and are arranged in an axial direction of the rotating shaft, and wherein the bypass passage extends in the axial direction of the rotating shaft of the driving section and allows the suction port and the discharge port to communicate with each other.
 4. The fluid machine according to claim 3, further comprising: a valve mechanism which opens and closes the bypass passage, wherein the valve mechanism opens and closes the bypass passage by displacing a valve body in the radial direction of the rotating shaft of the driving section.
 5. The fluid machine according to claim 1, wherein the fluid machine includes, as the driving section, a scroll section including a fixed scroll and an orbiting scroll, and includes, as the sliding section, an anti-rotation mechanism that prevents the orbiting scroll from rotating.
 6. The fluid machine according to claim 5, wherein the fluid machine is a scroll type expander, and is incorporated in a Rankine cycle device which recovers waste heat of an engine for a vehicle for use. 